PUF pipes application in the oil production industry
Many oil fields in Russia are located in Northern regions with prevailing sub-zero mean annual temperatures. Oil transportation under these conditions creates many challenges. One of the issues, for example, is the high viscosity of oil when it is transported in a cold pipe.
Ensuring the high efficiency of oil pipeline operation in a cold climate required a modernization of PUF pipes.l Maintaining continuous heating of the pipeline along its entire length is of utmost importance for the optimum oil transportation conditions. This task was solved by running a so-called “tracer pipe” close to the main pipe surface, covered by a layer of PUF and additional protective shell made of a polyethylene layer or galvanized steel.
The tracer pipe is made of mild steel, and inside the pipe is an isolated conductor which AC current is flowing through. This produces a “skin effect”, which consists in releasing heat energy by the tracer and its transmission into the main pipe in order to reduce the viscosity of transported oil.
Consequently, oil companies have to cooperate with those manufacturers of thermally insulated pipes, whose products are capable not only of minimizing heat losses, but also of ensuring the operating temperature of the pipeline along its entire length.
PUF pipes are equally in demand in southern regions. This is due to the PUF performance characteristics and its benefits as opposed to other thermal insulation materials. Also, in a hot climate standard PUF pipes may be used instead of pipes with the tracer.
Types of materials for thermal insulation of oil pipelines
A variety of materials with different performance characteristics may be used to ensure the required level of thermal insulation on oil pipelines:
|
PUF | Highly reinforced insulation | Liquid insulation* | Foam rubber |
---|---|---|---|---|
Thermal conductivity, W/(m·К) | 0,033 |
0,037 |
0/0358-0.739 depending on number of layers | 0,036 |
Density, kg/m3 | 80-100 | Up to 200 | 0,6-0,7 in liquid state | 40-80 |
Service life, years | > 30 | > 30 | > 15 | 10-20 |
Strength, MPa | 0,3 | 0,3 | - | - |
Material structure | Closed pores | Closed pores | Hollow | Porous |
Heat resistance | Moderately flammable | Moderately flammable | - | Weakly flammable |
Water absorption | None | 1% | None | 2,4% |
RRCS | Yes | No | No | No |
*In certain cases oil pipelines are thermally insulated using liquid insulation, which is essentially the application of thermally insulating paint containing hollow ceramic, glass or silica-alumina particles. However, this method is feasible for insulating only short sections of an oil pipeline and only indoors.
Преимущества ППУ в теплоизоляции нефтепроводов
Benefits of PUF for thermal insulation of oil pipelines
- The lowest level of heat losses, hence, prevention of temperature surges
- Water absorption is non-existent;
- May be used on above-ground and underground oil pipelines;
- Oil pipeline operation can be monitored using the rapid remote control system;
Pipes in polyurethane foam insulation are widely accepted throughout the world. In Europe alone, the share of PUF pipe application is around 70%. Although this figure is lower in Russia, the current trends indicate that PUF insulation is steadily replacing other heat-saving materials used on oil, gas and water pipelines.